Nucleotides & DNA/RNA structure and function

Question 1

What is the structure of nucleic acids (5)

Answer 1

Nucleic acids are made up of nucleotides made up of nucleosides containing:

1. 5 carbon sugar
2. Nitrogenous base on carbon 2
3. Phosphate group on carbon 5.

The sugar on the nucleoside is either deoxyribose, meaning without oxygen on carbon 2, or Ribose containing a hydroxyl (OH) group on carbon 2

Question 2

Discuss the biochemistry of nucleic acids (4)

Answer 2

1. DNA is structured so that the sugars of each strand are on the outside, while the bases hydrogen bond on the inside, resulting in what is known as the sugar-phosphate backbone.
2. The sequence of the bases on the inside is what makes up each individual being and is specific to them.
3. The sugar phosphate backbone is hydrophilic whereas the inside bases are hydrophobic.
4. The phosphate group from DNA is what gives it its negative charge.

Question 3

Outline how nucleic acids function at a molecular level (6)

Answer 3

1. Building blocks of nucleic acids
2. Driving force for a number of chemical reactions – ATP, GTP
3. Used in glycogen and complex carbohydrate biosynthesis
4. Used in complex lipid synthesis
5. Intracellular signalling molecules
6. Form parts of coenzymes (molecules that work with enzymes to help them with metabolic processes) – NAD, FAD, CoA

Question 4

How does the structure of nucleic acids relate to their function (6)

Answer 4

1. Nucleic acids carry genetic information that cells use to create RNA and proteins, which enable living things to function.
2. The double helix structure of DNA allows the molecule to copy itself during cell division.
3. The sequence of nucleotides in DNA forms an organism’s traits.
4. The sequence of codons in nucleic acids determines the sequence of amino acids in a protein.

With the primary structure of nucleic acids hydrogen bonds are formed between bases holding them together stabilising the pairing.

Three hydrogen bonds between C and G and two hydrogen bonds between A and T.

The secondary structure of DNA allows DNA to store, protect, replicate, and repair genetic information. It also allows drug targeting through the major grooves.

Question 5

Why is studying nucleic acids is important from a pharmaceutical perspective

Answer 5

Nucleic acids can be a target for drugs as the major groove is where drugs can be inserted.